Do you have a multi meter? With everything off, disconnect the negative battery cable and take an amp meter reading between the negative cable, and the negative battery post.
A few milliamperes would be expected, but start in the high amp range as I suspect you have high key off draw.
Typically the + side of the ignition switch, and the voltage regulator are connected to the battery, but check the diagram for your machine. If that is the case, and you have high key off drain, try disconnecting the voltage regulator and retest.
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